Oral mucositis (OM) is one of the most frequent and potentially serious side effects of non-surgical antitumoral treatment (1,2). Clinically, it is characterised by erythema, formation of ulcers with or without pseudo-membranes, bleeding, formation of exudates, and/or infections located at the upper level (3), and can evolve into a debilitating form which adversely affects the patient's quality of life. The damage to the mucous membranes can extend from the oral cavity to the pharynx; in this invention, therefore, the term “oral mucositis” includes mucositis of the pharynx.
The patient's perception of the symptoms associated with OM ranges from a sensation of pain in the mouth to impairment of various oral functions (4). OM can be associated with pain symptoms such as dysgeusia, dysphagia, and difficulty in speaking, chewing or swallowing, with consequent impairment of the ability to eat, weight loss, and the need for feeding through a nasogastric tube.
All this not only has an adverse impact on the patient's quality of life, but can also lead to discontinuance of the treatment or a reduction in the dose of antitumoral medicament, with a consequent decline in the patient's life expectancy (5). In financial terms, the frequent hospital admissions of patients suffering from OM, and their home care by personnel skilled in the administration of drugs or parenteral feeding, involve a considerable burden on the national health service (6,7).
Despite the severity and frequency of cases of OM and the many studies conducted on the subject, there is still no universally accepted standard strategy for the prevention and treatment of this potentially serious complication. Although some trials have demonstrated that the onset of OM can be prevented or reduced, they were conducted on an insufficient number of participants, and do not meet adequate standards which allow the drafting of clinical practice guidelines (8-11).
At present, the treatment of OM and the pain caused by it comprises: basic topical anaesthetics, systemic analgesics, anti-inflammatories, mucosa-coating agents, mouthwashes, oral hygiene in general, and antimicrobials (5,12-15). A number of other agents have also been tested, such as growth factors and cytokines, biological compounds that protect the mucosa, cryotherapy, and low-level laser treatment (13,16). Hyaluronic acid (HA) plays an important role in tissue healing, by means of various mechanisms (17-19); clinical trials have also confirmed that it improves the healing process of ulcers of the lower limbs (20) and the nasal mucosa after surgery (21) and reduces acute epithelitis in patients who undergo radiotherapy to treat head, neck, breast or pelvic cancer (22).
The research therefore focuses on new treatment strategies for oral mucositis and the corresponding formulations.
It was recently demonstrated that a gel based on 0.2% HA for topical use not only relieves the pain/stinging associated with recurrent aphthous stomatitis and atrophic/erosive oral lichen planus, but also contributes to the clinical resolution of areas presenting ulcers, erosions or atrophy (23,24).
WO 2007/048524 describes wound-healing pharmaceutical compositions comprising a combination of glycine, lysine, leucine and proline and sodium hyaluronan, which is particularly effective in facilitating the process of cell renewal that forms the basis of rapid wound-healing, promoting connective tissue reconstruction and consequent regeneration of the epithelial cells.
WO 2008/027904 discloses formulations of viscous polymers such hyaluronates or PVPs for treating stomatitis or mucositis. WO 02/39978 discloses enteral nutritional supplement for malnourished or chronically ill patients comprising glutamine, anti-oxidants and fatty acids. Glycine can be optionally present as a calcium antagonist.